Protection device for cannulae

ABSTRACT

The invention relates to a protection device for cannulae ( 12 ), comprising a cone-shaped insert element ( 16 ) on one end thereof, which is inserted into a cone-shaped insert of a corresponding syringe ( 10, 11 ) whereon a sleeve-type partial element ( 14, 17 ) is fixed. Said element can be guided to an end position as a result of the tension load, whereby the sleeve-type element covers the whole the tip of the cannula in a peripheral manner.

[0001] The invention relates to protective device for a needle having atapered end fitting that can be fitted on a complementary tapered mountof a syringe.

[0002] In order to inject active substances, syringes are used that havea piston-holding cylinder whose front end is provided with a central oroffset tapered mount over which can be slipped the tapered seat of anend fitting of a metallic needle. Such syringes are used in largenumbers as so-called single-use syringes that are disposed of after use.

[0003] The needle and its end fitting are sealed in a sterile packingand held in a protective cap formed as a quiver-like sleeve having anopen end whose internal dimension is such that it can fit is tightlyover the outer surface of the tapered mount. The doctor and medicalstaff are thus protected when unpacking the needle and fitting it to thesyringe end mount. Once the tapered end fitting is secured to the endmount of the syringe, the protective cap is pulled off so that aninjectable substance can be drawn in and then used for a subcutaneous,intravenous, or intramuscular objection or so as to draw body fluids,normally blood, from the patient. In order to prevent needle sticksafter use, the cap is fitted back over the front needle end, the endfitting of the needle is pulled off the syringe, and the needle insidethe protective cap is thrown out. The protective cap is made of plasticand is formed such that it does not bend even when severely stressed norcan it expose the needle tip. There remains however as a result of thesmall inside diameter of the protective cap the danger that the sharpneedle end misses it to create a substantial danger of injury and a highrisk of infection.

[0004] Medical personal are normally working very quickly and areoccupied with the patient, so that the needle is set aside after use.The used needle is left unprotected on the table and is often tossed asan “open needle” into the trash. When the trash is emptied by thecleaning personnel the needle pokes easily through the plastic garbagebag and can easily injure the personnel dealing with the trash since theneedles and syringes are not visible from outside.

[0005] In order to prevent this, German 3,904,559 proposes a protectivesleeve for the needle of a syringe that is formed of two pivotal jawsthat can be locked to each other so as to enclose the syringe needle ina tube-like space. The jaws are pivoted on the body of the syringe, on aseparate adapter, or on the bases of a specially designed syringeneedle. The disadvantage of this solution is that it is technicallycomplex and, in particular relative to standard production costs,expensive since the half-shell jaws must be locked together.

[0006] It has been proposed for injection needles that the needle bemounted on the piston in its full-forward position so that it can bedrawn back into the empty cylinder. A complex coupling is needed thatnot only increases the cost of the end product but also makes using theneedles after use more difficult, requiring at least particularattention and careful handling when fitting the needle end fitting tothe piston.

[0007] It has further been suggested to provide a longitudinallyslidable sleeve on the syringe body that is pulled forward after thesyringe is used and closed so that the needle point is covered.

[0008] The disadvantage of this system is that the diameter of thesyringe in increased (by double the wall thickness of the sleeve), thetapered end fitting can not be mounted at the very end of the syringebody, and it does not rule out the accidental insertion of a finger intothe sleeve. Even such an embodiment is not only expensive because of theconsiderable material used, but in particular because of the closure.

[0009] It is therefore an object of the present invention to provide aprotective device of the described type that is sufficiently safe, easyto use, and inexpensive to manufacture.

[0010] This object is achieved by the protective device of claim 1 inthat the end fitting carries a sleeve that can be pulled into an endposition in which the sleeve completely covers the needle tip. Bymounting the sleeve on the end fitting it has to start with the smallestpossible diameter so as not to present a large opening at its end. Itcan be made with little material. In addition the sleeve can be providedwith pulling means that are no bother and that can be gripped at a safespacing from the sharp sharpened needle end without any danger ofinjury.

[0011] Further embodiments of the invention are described in thedependent claims.

[0012] Thus according to a preferred embodiment of the invention thesleeve is connected with the tapered end fitting by a weakened region.The weakened region is formed as a very thin annular region thatconnects the tapered mounting part and the sleeve. Alternatively thesleeve is simply fitted frictionally over the end fitting so that oncethe friction is overcome it can be pulled off. This can be achieved forexample by frictionally engaging tapered surfaces. It is significantthat the sleeve is no hindrance when injecting or on drawing bodilyfluids and a sufficient length of the needle is exposed. Once thefriction connection is released or the weakened region is broken, thesleeve can be pulled “forward” in order to safely contain the tip.

[0013] Preferably between the sleeve and the end fitting there is atether), preferably at least one strand or string, whose length is suchthat it limits movement of the sleeve away from the end fitting beyondan end position. The maximum possible length of the string thus forms astop by means of which the sleeve is brought in to the desired position.

[0014] In order to protect the needle tip when it is unpacked and beforeit is fitted to the tapered mount of a syringe, a sleeve-shapedprotective cap is used that is loosely fittable over the needle and thathas an open end formed with a lateral slots of a width big enough forthe tethers to pass through. When for example there are to diametrallyopposite strings fixed on the end fitting, the slits of the protectivecap are also diametrally opposite so that the strings fit through them.At its simplest one tether, that is a string or strand, is enough buttwo tethers are safer since they allow one string to be torn off.

[0015] Since the end fitting with two (or more) slots is less stablewith respect to lateral bending, the end fitting has at least twoexternal tongues that are seatable in complementarily formed pocketsformed at an open end of the protective cap.

[0016] According to an alternative solution the sleeve is elastically orplastically extendable such that a top of the needle that is exposedshortly is completely covered by the sleeve before and after standarduse after drawing a bodily fluid or after injecting an active agent. Forexample the sleeve can be formed over at least a portion of its lengthas a bellows that provides the desires extensibility. The sleeve canalso be formed as small-diameter extensible telescope. Preferably thesleeve is readily bendable and is made of a material that is strongenough that it cannot be pierced by the needle. If the sleeve is pulledover the needle tip, its bendability leads to a modest deflection to theside so that the pointed needle end in particular its very sharp point,digs into the plastic inner surface of the sleeve and thus effectivelyprevents a retraction of the part that would expose the tip. In order toeffective protect the pointed needle tip before standard use, asleeve-shaped protective cap is provided for the needle that can befitted over the free end of the sleeve and fit with its taper.

[0017] Preferably the sleeve has a tentacle-shaped extension that in astarting condition, that is before standard use of the needle, endslevel with or slightly, e.g. 1 cm, past the needle tip and that isformed as actuating means for applying traction. This can be a plasticstrand or a flat extension that is elastic or flexible but bendable sothat it does not interfere with injecting or blood drawing. Thetentacle-like extensions form a system that in fact is usedautomatically. After inserting the needle in a vein, artery, or muscle,before bandaging the puncture site it is standard for the doctor ormedical assistant (nurse, aide, etc) to apply a pad to the puncture siteas the needle is pulled out. Application of the pad presses down thetentacle-like extensions so that as the needle is pulled out the sleeveis automatically pulled over the needle tip. At this time thetentacle-like extensions have done their job. The strength of thetentacle-like extensions or their tensile strength must not be too greatso that the tension serves merely to stretch the sleeve along theneedle. The tentacle-shaped extensions are positioned relative to theneedle tip, e.g. spaced some 5 mm, such that when the pad is applied tothe puncture site these extensions are engaged (right and/or left).

[0018] In order to ensure that the needles always lies in the desiredplane, the end fitting and the syringe mount are rotation symmetrical.

[0019] Preferably the sleeve has an inner wall provided withtongue-shaped spring elements that in an end position covering theneedle tip are engageable in pockets on movement of the part and resistopposite movement of the part. Such “barbs” are for example known foruse on the outside of anchors for screws. In this case the springelements do not project radially outward, but radially inward.

[0020] According to a further feature of the invention the sleeve has atan end on an inner surface annular niches in which the needle tip fitson return movement of the sleeve so as to prevent further returnmovement.

[0021] Embodiments of the invention are shown in the drawing. Therein:

[0022]FIGS. 1 and 2 show a first embodiment of the invention respectivebefore and after standard use of the needle in a partly sectionalperspective view;

[0023]FIG. 3 is a perspective view of another embodiment according tothe invention;

[0024]FIG. 4 is a detail view of a tapered end fitting with a sleeve,tethers, and tentacle-like extensions;

[0025]FIG. 5 is a perspective view of a protective cap;

[0026]FIG. 6 is a view of detail A of FIG. 3;

[0027]FIG. 7 is a section through a sleeve with barbs;

[0028]FIG. 8 is a section through a sleeve with an internal annularrecess.

[0029] The syringe shown in FIGS. 1 and 2 is comprised of a cylinder 10holding a piston 11 and provided at one end with an eccentric taperedmount over which can be fitted a complementary tapered end fitting 16 inwhich a needle 12 is imbedded. According to the invention the endfitting 16 carries a bellows 14 whose front end is provided withtentacle-like extensions 15 that extend parallel to the needle 12 andeven in this case slightly past it. The needle tip and the uncoveredparts are covered by a sleeve-like protective cap 13 whose open rear endis fitted over a complementarily shaped cylindrical or tapered surfaceof the sleeve-like part 14. The needle is thus covered along its fulllength. As a rule the needle is packed with the end fitting 16,protective cap 12, and bellows 14 separately from the cylinder 10 andpiston 11. Once the parts 10 and 11 and the parts 12-16 are separatelyunpacked the tapered end fitting is fitted to the tapered mount of thesyringe so that the needle is connected to the cylinder 10. Now theprotective cap 13 is pulled off so that the needle tip is exposed. Afterthe injectable medicament is drawn in through the needle 12, themedicament is injected subcutaneously, intravenously, orintramuscularly. As this is done the tentacle-like extensions 15 arepushed easily to the side by the skin and offer no hindrance to theinjection procedure of the needle even with a complex intravenousprocedure. Once the injection is complete as the needle is withdrawn aswab is applied to prevent bleeding. Application of the swab to the skinholds down the tentacle-shaped extensions 15 so that, as the syringe isbacked off, the bellows 14 is expanded to reach the position of FIG. 2in which the sleeve 14 is pulled over the needle tip. The bendableconstruction of the bellows of the sleeve ensures that, on any movementof the needle forward, the sleeve 14 bends to the side and is notpierced. When bent to the side as shown in FIG. 2 the needle digs intothe inside wall of the sleeve that is formed of such a strong materialthat the needle cannot pierce through it. Even when pushed strongly theneedle will at worst bend or break so that all pointed sharp parts areheld inside the sleeve.

[0030] In the embodiment of FIGS. 3 to 6 the tapered end fitting 16 isprovided with a sleeve 17 but a joint 18 to it is formed with a verythin wall thickness. A pull on the sleeve 17 ruptures the connection tothe tapered end fitting 16 so that the sleeve 17 can slide along theneedle 12 until it uncovers the tip of the needle 12. Here also thetentacle-shaped extensions 15 function on or shortly after withdrawal ofthe needle from the injection site to pull, first to break the weakenedjoint 18 and subsequently to move the sleeve 17 over the needle tip.Tethers 19 ensure that the part 17 is only moved to the region of theneedle tip. The sleeve 17 has internal pockets 20 in which springelements can engage when the sleeve. 17 is moved toward the tip of theneedle 12. FIG. 17 shows a spring element 27 engaged in such a pocket 20as well as a spread spring element 21. In an alternative arrangementshown in FIG. 8 an annular groove 28 in the sleeve inner surface isprovided forming a tapered widened region adjacent a restricted-diameterregion. When the sleeve-shaped extension 17 is pulled past the needletip, opposite movement of the needle engages the needle tip in therecess 28. FIG. 7 also shows a tapered widened region 26 that serves forcentering the needle in the sleeve.

[0031]FIG. 5 shows a protective cap 13 that has on opposite sides twoslots 23 through which the tethers 10 as well as the ends of thetentacles 15 are fitted (see in particular FIG. 6). In addition and asshown in FIG. 4 two tongues 24 are provided on the end fitting 16 thatfit in respective unillustrated pockets of the protective cap 13 andprevent this protective cap from bending. The protective cap's closedend has a wall thickening 25 to surely prevent any piercing by the sharpneedle tip.

1. A protective device for a needle (12) having a tapered end fitting (16) that can be fitted on a complementary tapered mount of a syringe (10, 11), characterized in that the end fitting (16) carries a sleeve (14, 17) that can be pulled into an end position in which the sleeve (14, 17) completely covers the needle tip.
 2. The protective device according to claim 1, characterized in that the sleeve (17) is connected with the tapered end fitting (16) by a weakened region (18) that preferably is formed as a very thin annular region or that the sleeve (17) is secured to the end fitting (16) by a releasable connection, preferably by frictionally engaging tapered surfaces.
 3. The protective device according to claim 2, characterized in that between the sleeve (17) and the end fitting (16) there is a tether (19), preferably at least one strand or string, whose length is such that it limits movement of the sleeve (17) away from the end fitting (16) beyond an end position.
 4. The protective device according to claim 3, characterized by a sleeve-shaped protective cap (13) that is loosely fittable over the needle (12) and that has an open end formed with a lateral slots (23) of a width big enough for the tether (19) to pass through.
 5. The protective device according to claim 4, characterized in that the end fitting (16) has at least two external tongues (24) that are seatable in complementarily formed pockets formed at an open end of the protective cap (13).
 6. The protective device according to claim 1, characterized in that the sleeve (14) is elastically or plastically extendable such that a top of the needle (12) that is exposed shortly is completely covered by the sleeve (14) before and after standard use after drawing a bodily fluid or after injecting an active agent.
 7. The protective device according to claim 6, characterized in that the sleeve (14) is telescopingly elongatable.
 8. The protective device according to claim 6, characterized in that the sleeve (4) is formed over at least a portion of its length as a bellows.
 9. The protective device according to claim 7 or 8, characterized in that a free end of the sleeve (14) is fittable on an open end of a sleeve-shaped protective cap (13) for the needle.
 10. The protective device according to one of claims 1 to 9, characterized in that the sleeve (14, 17) has a tentacle-shaped extension (15) that in a starting condition, that is before standard use of the needle, ends level with or slightly, e.g. 1 cm, past the needle tip and that is formed as actuating means for applying traction.
 11. The protective device according to one of claims 1 to 10, characterized in that the end fitting (16) and the syringe mount are rotation symmetrical.
 12. The protective device according to one of claim 1 to 11, characterized in that the sleeve has an inner wall provided with tongue-shaped spring elements that in an end position covering the needle tip are engageable in pockets (20) on movement of the part (14, 17) and resist opposite movement of the part (14, 17).
 13. The protective device according to one of claim 1 to 12, characterized in that the sleeve (14, 17) has at an end on an inner surface annular niches (28) in which the needle tip fits on return movement of the sleeve (14, 19) so as to prevent further return movement.
 14. The protective device according to one of claims 1 to 12, characterized in that the sleeve latches in an end position covering the needle tip so that when pushed back longitudinally the needle tip always remains covered.
 15. The protective device according to one of claim 1 to 14, characterized in that the sleeve (17) has on its end turned toward the needle tip a tapered widened region (26) of its inside wall. 